This invention relates to a furnace of the type having a combustion chamber for ignition of a fuel and air mixture and, in particular, to the means for controlling the discharge of the condensate and flue gas by-products of combustion.
Gas furnaces typically include a heat exchanger having a combustion chamber for combustion of a fuel and air mixture. The heat exchanger is designed to permit the passage of air over the combustion chamber. Often the heat exchanger includes a secondary heat exchanger to enhance the transfer of heat to a medium which is then directed to an enclosure for heating thereof.
Concomitantly with transfer of heat from the combustion products, the combustion products are cooled and liquid condensate will form during the heat extraction process particularly in the secondary heat exchanger. The condensate is typically collected and directed through a conduit from the heat exchanger to a drain. However, because the condensate may constitute an acid solution, it is common to direct the condensate products through an acid neutralizing media before it is passed into a drain.
Devices of this nature are disclosed particularly in Tomlinson et al, U.S. Pat. No. 4,543,892 entitled "Condensate Handling Means for Condensing Furnace". In Tomlinson et al, flue gas and condensate flow into a vertical tube. The flue gas products discharge upwardly through the vertical tube and the condensate products flow downwardly through the tube, through a trap at the bottom of the tube and then through a neutralizing media. In known embodiments of the device depicted in the Tomlinson et al patent, a styrofoam float is additionally provided within the vertical collection tube to block the flow of flue gas in the event the trap becomes somehow blocked. The float is buoyed by the condensate in such a circumstance to close the flue gas passage.
Other patents disclose similar furnaces and teach various ways to neutralize the collected condensate collected from the combustion products including Ketterer in U.S. Pat. No. 4,309,947 entitled "Mounting Arrangement for Condensate Neutralizer in a Furnace" and Tomlinson in U.S. Pat. No. 4,289,730 entitled "Furnace with Flue Gas Condensate Neutralizer". The concept of collecting condensate from a heat exchanger is also taught in Herbert U.S. Pat. No. 3,212,288 entitled "Heat Exchanger with Condensate Collector".
The various referenced prior art patents disclose highly useful and efficient means for collecting condensate and discharging flue gas from a hot air furnace and, in particular, a gas hot air furnace. However, there has remained a need to provide an improved trap assembly associated with such furnaces. That need inspired the development of the present invention.